This invention relates to dispensing closures of the kind which have a self-closing valve, and to methods of assembling such closures. By self-closing valve is meant an essentially unitary valve which is moulded from an elastomeric material and which in use opens in response to an elevated pressure created in an associated liquid product, and closes again automatically and in a self-sealing manner when the pressure is subsequently reduced to ambient pressure. Self-closing valves have been proposed for use with a wide variety of liquid foods e.g. ketchups, and household products e.g. washing-up liquids.
It is well known to provide a dispensing closure with a self-closing valve which is a unitary component formed basically of three parts, namely (a) a dispensing head formed with a dispensing opening capable of self-reclosure after a dispensing operation, (b) a mounting ring by which the valve as a whole can be mounted in a closure body, and (c) a connecting wall connecting the head and the ring to one another.
The dispensing head and usually also the connecting wall is required to be flexible in order to perform its desired functions. Being of the same, relatively thin, material as the head and the wall, the mounting ring will itself be subject to distortion in response to the substantial forces which may be imposed upon it during dispensing. It is nevertheless required to make a secure seal with the closure body against leakage of product.
In the dispensing closures with self-closing valves which have met commercial success hitherto, the mounting ring has been secured in the closure by means of two components of the closure body which are snap-engaged together so as to hold the mounting ring between them in a sealing manner. However, although such arrangements have been satisfactory in terms of their operating performance, they have had a high manufacturing cost arising from the three components and the need to assemble them together. In some arrangements the mounting ring has been bonded or otherwise attached to a support ring prior to assembly in the closure, and this has further increased the cost of manufacture.
The present invention seeks to enable a self-closing valve to be secured in a closure in a manner which combines low manufacturing cost with high seal integrity. Accordingly from one aspect thereof the invention provides a method of securing a self-closing valve having a mounting ring in the assembly of a dispensing closure, the method being characterised by the following steps:
a) providing the closure body with a downwardly directed abutment face surrounding a dispensing aperture in which the valve is to be located, and a generally cylindrical skirt dimensioned to accept the mounting ring and extending downwardly of the closure to a free edge axially spaced from the abutment face, a portion of the skirt including the free edge being inwardly deformable;
b) providing the mounting ring of the self-closing valve with an upwardly directed abutment face engageable with the abutment face of the closure body;
c) entering the valve into the skirt of the closure body with the abutment faces in opposition; and
d) inturning the deformable portion of the skirt against the mounting ring so that it holds the mounting ring with the abutment faces in mutual abutment and with the closure body and the valve in sealing relation. Preferably a seal between the closure body and the valve is provided at the interface of the abutment faces.
From a second aspect the invention provides a dispensing closure on or for a container, which comprises a closure body having a dispensing aperture, a downwardly directed abutment face surrounding the aperture, and a generally cylindrical skirt extending downwardly of the closure to a free edge spaced from the abutment face, the closure further comprising a self-closing valve having a mounting ring formed with an upwardly directed abutment face, the valve being received within the skirt with its abutment face abutting the abutment face of the closure body and held there by an inturned and resilient portion of the skirt including the free edge thereof, the closure body and the valve being disposed in sealing relation preferably at the abutment faces.
In the two preceding paragraphs the inturning of the free edge portion of the closure body skirt is preferably done by a mandrel, possibly heated and possibly formed of two or more relatively movable parts, which is brought into engagement with the closure body skirt after the valve has been inserted into the skirt. As an alternative, however, one or more rollers which are moved progressively around the circumference of the free edge portion may be used.
In order that the invention may be better understood two dispensing closures and a method of assembling them in accordance with the invention will now be described by way of example, with reference to the accompanying drawings which in which: